OAK BROOK, Ill. (AP)  McDonald's (MCD) is considering whether to require its processors to use a method for slaughtering poultry that animal rights groups say is more humane.

The fast-food giant said it is studying the possibility of "controlled atmosphere killing," in which chickens are put to sleep with gas, such as nitrogen or argon.

McDonald's animal welfare council suggested a study of the newer method, said Bob Langert, McDonald's senior director of social responsibility. It would replace a slaughtering process in which chickens are hung by their legs on a moving conveyor line and pulled through an electrified vat of water.

"There has been very little study of this process as to impact on animal welfare," Langert said Wednesday.

Some of McDonald's European suppliers already use the newer method, the company said. McDonald's will post the results of the study on its Web site by June 30, said Patricia Paul, senior director of corporate governance.

McDonald's move followed an announcement by People for the Ethical Treatment of Animals, which said it would submit a proposal on the issue for consideration by shareholders at McDonald's annual meeting.